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WinTV HVR-1300
July 25th, 2009 under Linux. [ Comments: none ]

Update on how to get the WinTV HVR-1300 working under linux.

Most of the configuration remains the same as described here. The major differences is the issue with the firmware and the IR.

If you encounter a message in the dmesg like “ERROR: v4l-cx2341x-enc.fw missing” then you don’t have the appropriate firmware. The firmware can be obtained at http://dl.ivtvdriver.org/ivtv/firmware/ivtv-firmware.tar.gz. Simply copy the content of this file to /lib/firmware (this might be different on non Arch Linux distros). This should fix the above error message.

As for the IR Remote Control, I experienced that the ir_kbd_i2c module doesn’t generate a /dev/input/eventX anymore. However, with the HVR-1300 it is also possible to use the driver proveded by LIRC. Make sure you compiled the LIRC with –with-driver=all or –with-driver=hauppauge. Then we can modprobe the appropriate modules, namely lirc_i2c. This results in a new device /dev/lirc0 (or something alike). Now, we can use the lircd command as usual (for the driver we use default). The only thing remaining is to configure the remote by using irrecord. This results in lircd.conf.

That’s it, everything should be working now.

CUDA and Critical Sections with Locks
July 21st, 2009 under OpenGL. [ Comments: none ]

I had the following problem:

Each CUDA Thread might possible write to any cell in a 3d array in global memory. Thus, some synchronization is required.

The easiest solution is using the atomic operations which are provided by CUDA. Unfortunately, the performance isn’t great. Therefore, I tried improving the performance by implementing a locking mechanism of my own. Simply, using a lock.

The result was that this approach is absolutely useless. I experienced a performance loss of nearly 1000x

GLSL Samplers
July 7th, 2009 under OpenGL. [ Comments: none ]

I just tried to find a bug in my texturing shader. Unforunatelly, I forgot to set the filtering parameters. As a result, the sampler in the shader always returned 0.

Hopefully I learnt my lesson

REMEMBER: Always set the filtering parameters for textures if you want to do textureing!!!!!